superbit? What is it?

I just bought another DVD to add to my collection. I had a choice to buy the fifth element on regular dvd or superbit. Difference in price is $10.00; don't mind spending the extra, but can anyone tell me if there is truely a difference in sound? Also will superbit be the next generation of dvd's and should I be buying them? Just looking for some help from the guru dvd experts. As always, thanx for your help in advance. Pete